1. Field of the Invention
The present invention relates to the production of a smart antimicrobial system to inhibit microbial growth. Endogenous chemicals, such as metabolites produced from bacteria are utilized as chemical substrates and then converted by enzymes to produce disinfecting compounds that in turn inhibit the targeted microorganism.
2. Description of the Background Art
Biocides and more specifically, antimicrobials are commonly used in medicine and agriculture to control the population of undesired organisms. Most biocides are not specific in killing a particular type or class of organism and have negative effects on other (non-target) cells and tissues and can be harmful to the environment.
Furthermore, the use of silver containing products for wound treatment involves the risk of both argyria, or silver toxicity (Abraham T. Wan et. al., Determination of Silver in Blood, Urine, and Tissues of Volunteers and Burn Patients, 37 Clin. Chem. 1683, (1991); Alan B. G. Lansdown, A Pharmacological and Toxiological Profile of Silver as an Antimicrobial Agent in Medical Devices, 2010 Advances in Pharmacological Sciences, (2010).) and the emergence of resistant organisms (E J L Lowbury et. al., Topical chemoprophylaxis with silver sulphadiazine and silver nitrate chlorhexidine creams: emergence of sulphonamide-resistant Gram-negative bacilli, 1 British Medical Journal 493, (1976)). Tributyltin, widely used in anti-fouling treatments for maritime vessels since the 1960's, has been shown to persist in the environment and have adverse effects across many species (Taisen Iguchi & Yoshinao Katsu, Commonality in Signaling of Endocrine Disruption from Snail to Human, 58 BioScience 1061, (2008); International Maritime Organization, Anti-fouling systems (2002)). This necessitates diligence in deploying such non-specific biocides, as their use should be avoided when the targeted biologicals are not present at problematic concentrations.
However, biocides must be readily available as soon as conditions change and the hazard has exceeded a ‘threat’ concentration. The object of this invention is to define a protein polymer material that generates biocides and antimicrobials only when conditions dictate that disinfection is necessary. Appropriate ‘triggering’ environmental conditions include, but are not limited to, signs of physical activity such as increases in body temperature and perspiration, signs of microbial contamination including volatile and non-volatile organics produced as metabolic products from propagating organisms (including excreted proteases, organic acids, and biogenic amines) as well as conditions in the environment that may foster microbial growth including excess humidity, bodily fluids and waste materials, and the presence of exopolysaccharide. There are no materials currently which specifically produce antimicrobial compounds, such as oxidizers, only when the target organism is present. Most of the materials currently available either require activation prior to use or are active immediately out of the package.
Hydrogen peroxide, an oxidizer, has been used for many years to disinfect wounds. One problem is that its rapid breakdown into water and oxygen make it difficult to use for prolong periods of time. Also very high concentrations (>3%) of hydrogen peroxide are toxic to the host cells. That is why it is important for an on demand source of an oxidizer, such as hydrogen peroxide, to disinfect wounds only when ‘triggering’ conditions are present.
U.S. Pat. No. 6,228,128 Johansen discloses treatment of microorganisms and/or viruses comprising treating said microorganisms and/or viruses with an effective amount of fungal lactase enzymes and an effective amount of one or more enhancers in the presence of oxygen. The enzyme here requires enhancers for the invention to work effectively and the enzymes are always active after activation.
U.S. Pat. No. 7,927,588 Davis et al. discloses a dressing containing an enzyme and a dressing containing a water source for the dressing to be activated. It was not suggested that the enzyme could be turned on by ‘triggering’ conditions.
U.S. Pat. No. 7,731,954 Davis et al. discloses a skin dressing comprising oxidoreductase enzyme wherein the enzyme is present in a hydrated condition. The enzymes are hydrated prior to use and are always active. U.S. Pat. No. 7,731,954 can only last for up to 2 days after activation. The invention does not respond to environmental conditions and the ingress of catalase is an efficiency reducing condition. It does not proscribe a way to inhibit catalase from using the hydrogen peroxide that is produced from the oxidoreductase enzyme nor a way of being active longer than 2 days after application.
U.S. Pat. No. 7,713,955 Whiteford et al. describes antimicrobial coatings for a surface. It discloses using a bridged polycyclic compound based coating system to impart self-cleaning properties to a surface. It does not disclose using enzymes that are can be activated by the environment that produce oxidizers when a target organism is present.
U.S. Pat. No. 6,759,220 LeJeune et al. discloses the loading of an enzyme into a polymer and how to improve the loading. It does not disclose having the enzymes only activated by the environment. It further does not teach that the polymers could be for anti-microbial purposes nor as a dressing.
It is desirable to make a material which generates antimicrobial compounds when a target organism is present, the material does not need a substrate to work and can be employed for long periods of time, such for example but not limited to, a time period of greater than three to four weeks.